The instant inventions relates, generally, to the field of measurement instruments, and, more specifically, to devices that measure the length of an interior or exterior wall by indirect optical means.
In many fields of endeavor, such as real estate appraisal, architecture, engineering, and building inspection, it is necessary to measure the length of an interior or exterior wall. It is often difficult to get close enough to the wall to use, for instance, a measuring tape due to obstructions, vegetation, or jags in the direction of the wall.
A number of measuring solutions have been suggested. M. Fox (U.S. Pat. 3,908,281) suggests a real estate appraisal instrument and method. However, this instrument requires that an object of known dimension be observed and such an object is not always available. R. Genho (U.S. Pat. 3,897,637) proposes a laser level and square that does not provide any measuring means but merely provides a laser-generated line that defines a level. J. Rando (U.S. Pat. 5,287,627) provides an automatic plumb and level tool with acoustic measuring capability. This device is very useful in providing a means for measuring the distance to a laser-illuminated object but does not provide means for measuring the length of the object itself.